DD - thank you - but you are far to generous. I am so ignorant I did not understand my own question.
But I did learn from the answers.
My thanks to you and Peter.
I do think the potential of IVIG for AD looks promising.
ij
It is astonishing what foolish things one can temporarily believe if one thinks too long alone ... where it is often impossible to bring one's ideas to a conclusive test either formal or experimental. J.M. Keynes